Neurotransmitter Mechanisms in Depression and Anxiety Disorders

Depression and anxiety disorders arise from complex disturbances in brain chemical signalling. Key monoamine neurotransmitters—serotonin, noradrenaline and dopamine—regulate mood, motivation and arousal, and their dysregulation can stem from reduced release, altered receptor responsiveness or impaired intracellular signalling. Neuropeptides such as galanin, neuropeptide Y and oxytocin modulate these classic transmitters and integrate stress responses via the hypothalamic-pituitary-adrenal axis. Emerging evidence highlights the role of heteroreceptor complexes—assemblies of different G-protein-coupled receptors—whose allosteric interactions influence neuronal excitability through effectors like G protein-coupled inwardly rectifying potassium channels. Gene–environment interactions, including stress-induced epigenetic modifications, further shape individual risk. Advances in understanding these molecular and circuit-level mechanisms are guiding novel therapeutic strategies, from precision augmentation in treatment-resistant cases to compounds targeting receptor heteromers and neuropeptide systems.

Research from Nature Portfolio

Analyses of functional genetic polymorphisms under varied stress exposure have revealed robust gene–environment interactions and epigenetic modulation of risk. Key findings indicate that specific receptor-encoding genes are only behaviourally relevant under moderate or high stress, emphasising the necessity to account for environmental context in genetic studies. Interactions between brain-derived neurotrophic factor and serotonin-1A receptor variants demonstrate how convergent molecular pathways mediate vulnerability. This work identifies candidate targets—such as galanin-2 and purinergic receptors—for next-generation antidepressant development and supports a causative model in which environmental stress, shaped by genetic susceptibility, precipitates neurotransmitter imbalances.

Neurotransmitter Mechanisms in Depression and Anxiety Disorders publication trend

The graph below shows the total number of articles in neurotransmitter mechanisms in depression and anxiety disorders across all publications each year (not limited to Nature Index journals).

Technical terms

Monoamine neurotransmitters: Small molecules (serotonin, noradrenaline, dopamine) that modulate mood and arousal.
G protein-coupled inwardly rectifying potassium (GIRK) channels: Ion channels that mediate inhibitory currents following receptor activation, regulating neuronal excitability.
Heteroreceptor complex: Assembly of different G-protein-coupled receptors whose protomers influence each other’s signalling.
Allosteric modulation: Regulation of receptor function through binding at a site distinct from the orthosteric ligand-binding pocket.
Hypothalamic-pituitary-adrenal (HPA) axis: Neuroendocrine system controlling stress responses via corticotrophin-releasing hormone and glucocorticoids.
Auto-receptor: Presynaptic receptor that regulates neurotransmitter release from the same neuron.

References

1. 5HT1AR-FGFR1 Heteroreceptor Complexes Differently Modulate GIRK Currents in the Dorsal Hippocampus and the Dorsal Raphe Serotonin Nucleus of Control Rats and of a Genetic Rat Model of Depression. International Journal of Molecular Sciences (2023).
2. A new pharmacological strategy against treatment-resistant depression. Progress in Neuro-Psychopharmacology and Biological Psychiatry (2024).
3. Emotional Roles of Mono-Aminergic Neurotransmitters in Major Depressive Disorder and Anxiety Disorders. Frontiers in Psychology (2018).
4. Neuropeptide and Small Transmitter Coexistence: Fundamental Studies and Relevance to Mental Illness. Frontiers in Neural Circuits (2018).
5. The Role of Central Serotonin Neurons and 5-HT Heteroreceptor Complexes in the Pathophysiology of Depression: A Historical Perspective and Future Prospects. International Journal of Molecular Sciences (2021).
6. Significance of risk polymorphisms for depression depends on stress exposure. Scientific Reports (2018).
7. Anxiety and Depression: What Do We Know of Neuropeptides?. Behavioral Sciences (2022).
8. Novel Pharmacological Approaches to the Treatment of Depression. Life (2022).